Possible health risks of manganese levels above RDA but below UL


Continuing the discussion from Schmilk… cheaper AND tastier than People Chow?:

@SoylentModerator, I created the new thread and think that all replies as part of the discussion to the quoted section and beyond should be moved to this thread.

EDIT: tagging @Tesseract and @BoDuke just in case the other tag isn’t being monitored…


What I get from this, is that throughout our lives, the constant consumption of Manganese builds up and can cause higher prevalence of neurological signs of CMnP, and show higher Mn concentration in hair.

After reading the study briefly, it appears they found no difference between areas A,B and C (which all had different levels of manganese in the water). They did however find differences between sexes and blood concentration. Which is interesting.


They did find neurological symptoms which were proportional the the concentration of manganese in the water.


Thanks for that! Question though. If your drinking water is contaminated with manganese, isn’t it a bigger issue because you would still be eating foods containing manganese? Whereas Schmilk would displace food consumption. In either case if your drinking water is contaminated I would point to that as a much bigger issue than increased dietary consumption.

And, apologies because I am definitely not a scientist, but does it even talk about an upper daily limit there? It seems to be talking about concentrations of manganese in the hair (i.e., what has built up over time, rather than what is consumed daily to reach that concentration in the hair).

This is another good reason to filter or at least periodically test your drinking water, though.


The concentrations were below the UL in water that was not ‘contaminated’. It was normal drinking water. And normal drinking water has varying levels of manganese. And so do some of our beverages like our foods.

That study was about ‘ingested’ manganese whether through food or water. And it showed that ingested manganese even below the 11mg/day is not safe always. And the build up in the hair is an outward indication of inner manganese overload.


minerals in the water make it yummy :slight_smile:


I filter my tap water because it doesn’t taste good. If someone is drinking water in order to drink water, I would say the presence of any other minerals could therefore be a contaminant? It’s kind of a semantics argument. I don’t think anyone drinks tap water to ingest manganese and I suspect you agree. The link you posted says “high manganese concentration in drinking water.” I take that to mean not low or average, but high. So I think testing for manganese (and other contaminants) or filtering your water is probably a good idea.

Forgive my ignorance but I don’t see that in the link you posted. Could you quote the relevant line? What I found on the FDA website was a reference to an upper limit of 11mg/day. I did find a thread here referencing WebMD:

People who have trouble getting rid of manganese from the body, such as people with liver disease, may experience side effects when taking less than 11 mg per day.

So that’s good to know if you have liver disease.

I suspect we feel the same about excess manganese but if the FDA thinks 11mg/day is fine I still haven’t seen anything that really contradicts that (unless you have liver disease). I would obviously prefer 2mg/day but I haven’t seen evidence that I would be poisoning myself with less than 11mg/day.


It talks about the concentrations of manage manganese in the water, but I didn’t see anything in there about the total amount of manganese ingested. Additionally, within that context, it could simply be that the consumption of it without food to blunt the absorption levels pushed the manganese levels higher than the body could deal with.

I can’t see anything in here that can be applied to the consumption of manganese in food or gives any evidence for a danger of consuming manganese in food at high but sub-UL levels. And given that current research has placed the UL at 11mg per day, I would have to assume that the water is a special case and that manganese is safe provided that it is below the UL.


Yes. I never implied that it isnt. But how many people test for it? Also we ‘ingest’ water right? So that is ingested manganese. Also yes webMD says people with liver disease have trouble excreting manganese from the body. But it doesnt mean high level manganese consumption does not causes side effects in the bodies of normak people, like the study shows.

What was the study i posted then?

The thing is organisations like FDA, once they take a position on an issue ( say like 11 mg upper limit for manganese ) dont change their stance if another or study or two find fault with the limits FDA sets. They do it only if multiple tests confirm it and then and coax and petition FDA to change it stance. Govt organisations are like that, not just in the states but every where. So if you want to wait until FDA changes its position on the UL of manganese it will take years.

Anyways, its upto you whether you consider the findings of this study or not. The study i posted is for anybody for whom this matters.


Total manganese ingested will be more than the amount we ingest from water alone no?

Are you saying they are not eating food at all?

It is not for food. I posted the study to make two points a) manganese in the water we drink alone can reach levels that can cause us harm, b) manganese below UL can cause harm too. So its better for us that we get as less manganese as possible from our food. And not just from water, we get some amounts from our beverages, and in air too in some areas

Refer to my comment to wezaleff.



Its possible that the RDA is more than the amount contained in this water sample. I’m actually tempted to do the math… If the total amount in the water sample is below the RDA, would you then consider getting the RDA value to be dangerous as well?

No… I’m saying that the manganese from the water is likely not consumed at the same time as food. Nutrients are typically absorbed more slowly with food, due to it being mixed in with other stuff. So, my point is that since it was in a more concentrated/unblunted form in the water, it might have been absorbed at a faster rate than in food.

You’re either misunderstanding or misrepresenting the study you linked to… the title of the study makes it clear its talking about “high manganese concentration”. This implies that the level of manganese in the water was abnormally high.

As I stated above, its likely that the concentration in the water resulted in a more dramatic uptake of manganese than it would in food. We would need a study on the equivalent amount in food to be sure that its the total amount of manganese that’s at fault, not the concentration and particular form of it.

Additionally, I’d like to point out that the study title shows that the researchers themselves didn’t think it was conclusive. They said it was “possible” not “actual”, sometimes initial studies pan out, sometimes they don’t. If you’re not willing to take that chance, that’s your decision, but you do not have sufficient grounds to demand everyone else be as overcautious as you.



It might have. But whats the link between the speed of absorption and manganese side-effects? Also what if it doesnt depend on speed of absorption?

Yes we do. But until then what do we do?

In ‘drinking water’ which people drink everyday. The point is when manganese can be found in drinking water in levels that can cause effects, its prudent to keep our mang consumption in food to a minimum.

This was the conclusion of the study ‘‘These results indicate that progressive increases of Mn concentration in drinking water are associated with progressively higher prevalances of neurological signs of CMnP and Mn concentration in hair of older persons.’’ And where and when did i demand?. I was suggesting. But you seem to be demanding from me not to inform others of this. I have a right to share with people what i know about something on the appropriate forum. How people take it its upto them. If i tell you or suggest you something, then you can ask from me that, but not when i do it to others. You do not have sufficient grounds to tell me what to tell other people.


On this topic, among others…

If you really do intend it is a suggestion, I would consider rephrasing because you usually phrase it as “do this and do that” rather than “I suggest” or "based on [study] I’d be careful consuming this much manganese. Additionally, I didn’t tell you what to tell other people. I said you don’t have a strong enough position to make your suggestions as forcefully as you appear to do. This may just be a communication issue, though.

I really do think you need to re-examine the study and the conclusions you’re taking from it.

Then you’re effectively forcing yourself into a position where there is no safe outcome, should this be the case. Levels of manganese below the RDA are known to be unsafe (on average), and if we were to accept your reasoning, the RDA would also be an unsafe amount. What then would be an appropriate amount to take in this scenario? Calculate the exact means at which we get poisoned the least? From whichever origin of species theory you fall under, the idea that our body has only malnutrition and poisoning as options seems ridiculous…

That being said, it turns out that the high range of the estimated daily amount of manganese is significant in sample b. I’m putting my calculations and results in this reply so we can move forward on more realistic numbers rather than conjecture. The study said there was a positive correlation between the concentration of the manganese and the symptoms of manganese poisoning. So let’s work with the area B sample and treat the area A sample as a control group.

The Mn concentrations in area… B… [was] 81.6-252.6 micrograms/l

According to the Mayo Clinic, the recommended water intake is 3L for men and 2.2L for women. Combined this figure with the concentrations of manganese in area in the study we get a range of 0.2448-0.7578 mg per day for men and 0.17952-0.55572 mg per day for women. Converted to an RDA percentage, the numbers are 20-63% for men and 15-46% for women.

I’ll have to admit that those numbers are significant… But out of curiosity, did you even attempt to do similar calculations? I probably would have taken you more seriously at the beginning had you presented these numbers.

The speed of absorption affects how concentrated the manganese or really any absorbable entitiy gets in the bloodstream. That’s why its typically not recommended to drink on an empty stomach: the faster it enters the bloodstream, the greater likelihood that it will overwhelm the body’s cleanup processes and create a toxic concentration that will actually affect the body. Additionally, toxicity is measured in concentration (how much of the stuff per kg of body weight) not total amount, so its the concentration in the body that defines whether it becomes toxic or not, in most or all cases.

That being said @SoylentModerator, can you move our discussion to a new topic? Our side thread is getting too large that it probably shouldn’t continue on this thread. Please leave the initial comment by @Tark


I don’t test for it but I do filter my water to remove whatever else is in there. When I want to drink water, I don’t want anything else in there (or I would add it myself!). That seems to be a more obvious suggestion than changing your diet because there is X amount of manganese in your water (well, there might be, but you can’t know if you don’t test or filter it).

Either my reading comprehension is poor or that study you linked said nothing about how much total manganese was consumed each day. I don’t know if it was below, at, or above the upper limit. Am I missing it? I admit that I might be, but you haven’t said otherwise if that’s the case.

Did the study you quote say anything about the UL for manganese? What should it be if not 11mg? 10? 9? Replacing the UL will be difficult if you don’t have a number. You seem to be insisting that 11mg isn’t safe without any alternative number proposed. At this point I absolutely put more stock into the FDA than I do your opinion. I haven’t seen any evidence presented to change my mind, much less solid evidence.


I am asking you specific examples.

So posting the study was not enough, i had to do the all the calculations from the study for you?

I am asking again whats the link between speed of absorption and the reported side-effects. Just saying it it typically recommended isnt enough. The proof of the actual link.

True. But How much stuff per kg of body weight also depends on how much we ingest no?


I’m not sure what @Tark has against manga. Maybe he should try reading some Naoki Urasawa.


Based on what you said, and based on what i know (correct me if i am wrong) filtering water doesnt remove manganese in it. Also yes we cannot know until we test for it. Infact there are waters which likely have little to little to none. But since we dont and its more likely that manganese will be there (it naturally occurs in varying concentrations in drinking water) , and since because of this it is harder to avoid it, the best we can is reduce it from our food.

There is no alternative number in the study or that i am aware of, i wish there was. If you want to put more stock into the FDA its your prerogative. I only shared what i know about it. If that doesnt seem like evidence to you, ignore it. I dont want to ‘force’ it as evidence.


Honestly back of my mind i was beginning to think that this would be the last time i’ll be talking about manga, after i posted my initial comment to wezaleff. And then the discussion with livingparadox happened :smile:


It depends on the type of manganese. Distillation would also work.

So if we need 2mg/day and mustn’t exceed 11mg/day, and our drinking water contains Xmg/day, we then need to eat Ymg/day in order to make up the difference. How are we supposed to solve for Y without knowing X? Even if 11mg/day is wrong, the problem remains.


So according to your link only a water softener and filter together remove both forms of manganese.

And we dont know X. And yes even if 11 mg is lowered to say 10 or even 7 the problem remains. So in my opinion instead of trying to consume below or above a certain number, we could distill water or avoid consuming manganese rich foods and drinks as much as possible.